A Cyclospora illness outbreak tied to Kwik Trip stores has worsened, with about 50 people now having reported they were sickened from vegetable trays that contained broccoli, cauliflower, carrots and dill dip.

Kwik Trip has removed the 6-ounce and 12-ounce trays from its stores, according to state health officials. The trays may also have been available from other businesses, not yet named by health agencies, officials said.

Cyclospora is a parasite commonly found in developing countries. During the summer, outbreaks and illnesses occur from contaminated fresh produce entering the U.S. from endemic countries.

As of Thursday, the number of Cyclospora cases suspected from the Kwik Trip vegetable trays sold in Wisconsin had risen from 11 to roughly 30 in less than a week, and 20 more cases were reported in Minnesota.

Cyclospora infections are relatively rare in Wisconsin. Almost half of the 60 cases reported so far this year were connected with the Kwik Trip vegetable trays produced by Del Monte Foods, according to state health officials.

Symptoms of Cyclospora infection include diarrhea, loss of appetite and weight, cramping, bloating and gas, nausea and vomiting.

Washing of imported produce is unlikely to kill the parasite, which can only be seen with a microscope. The infections are not spread from person-to-person.

If untreated, the illness may last more than a month and could continue over a recurring cycle, health officials said. To test for the presence of the parasite, stool specimens must be collected and sent to a laboratory

Thursday, an Eau Claire woman sued Kwik Trip and Del Monte for having become ill from the vegetable trays she purchased in Eau Claire. A similar lawsuit was filed by a woman from St. Charles, Minn.

Averie Goodman of Eau Claire has been ill for weeks, according to her attorney, Ryan Osterholm of Minneapolis.

Osterholm said he’s been contacted by about 35 people this week claiming they were sickened from the vegetable trays.

“It’s hard to predict right now, but I would not be surprised if there are hundreds of cases in Wisconsin,” he said.

“Every single person I have talked with has eaten this very particular item,” he added.

La Crosse-based Kwik Trip, which has stores across Wisconsin and Minnesota, is cooperating with state health officials in their investigation. Del Monte, which produced the vegetable trays for Kwik Trip, did not respond to questions from the Milwaukee Journal Sentinel.

Minnesota also is investigating another Cyclospora outbreak stemming from Sonora Grill in Minneapolis. So far, 17 people have reported illnesses.

“If you ate at Sonora Grill during the weekend of May 18-20, please contact the Minnesota Department of Health Waterborne Diseases Unit,” state officials said.

Nationwide, from May to August 2017, there were 206 cases of Cyclospora infections reported by the U.S. Centers for Disease Control and Prevention, up 134 percent from 88 cases reported in the same period in 2016.

Previous U.S. outbreaks have been linked to imported fresh produce such as basil, cilantro, lettuce, raspberries and snow peas. Most cases in the U.S. have been reported in the spring and summer.